From aa328c0bbd5f2afb888e2887eeed398b4901fe22 Mon Sep 17 00:00:00 2001
From: Camilla Berglund <elmindreda@elmindreda.org>
Date: Sun, 15 Jul 2012 16:48:39 +0200
Subject: [PATCH] Added support for GLX_MESA_swap_interval.

---
 readme.html        |  2 +-
 src/x11_opengl.c   | 18 ++++++++++++++++--
 src/x11_platform.h |  6 ++++++
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/readme.html b/readme.html
index faf6a52e..b854a59c 100644
--- a/readme.html
+++ b/readme.html
@@ -335,7 +335,7 @@ version of GLFW.</p>
   <li>[Cocoa] Bugfix: The cursor position incorrectly rounded during conversion</li>
   <li>[Cocoa] Bugfix: Cursor positioning led to nonsensical results for fullscreen windows</li>
   <li>[Cocoa] Bugfix: The GLFW window was flagged as restorable</li>
-  <li>[X11] Added support for the <code>GLX_EXT_swap_control</code> extension as an alternative to <code>GLX_SGI_swap_control</code></li>
+  <li>[X11] Added support for the <code>GLX_EXT_swap_control</code> and <code>GLX_MESA_swap_control</code> extensions as alternatives to <code>GLX_SGI_swap_control</code></li>
   <li>[X11] Added the POSIX <code>CLOCK_MONOTONIC</code> time source as the preferred method</li>
   <li>[X11] Added dependency on libm, where present</li>
   <li>[X11] Added support for the <code>_NET_WM_NAME</code> and <code>_NET_WM_ICON_NAME</code> EWMH window properties</li>
diff --git a/src/x11_opengl.c b/src/x11_opengl.c
index dc2788c8..e39d858c 100644
--- a/src/x11_opengl.c
+++ b/src/x11_opengl.c
@@ -544,6 +544,15 @@ int _glfwInitOpenGL(void)
             _glfwLibrary.GLX.SGI_swap_control = GL_TRUE;
     }
 
+    if (_glfwPlatformExtensionSupported("GLX_MESA_swap_control"))
+    {
+        window->GLX.SwapIntervalMESA = (PFNGLXSWAPINTERVALMESAPROC)
+            _glfwPlatformGetProcAddress("glXSwapIntervalMESA");
+
+        if (window->GLX.SwapIntervalMESA)
+            window->GLX.MESA_swap_control = GL_TRUE;
+    }
+
     if (_glfwPlatformExtensionSupported("GLX_SGIX_fbconfig"))
     {
         _glfwLibrary.GLX.GetFBConfigAttribSGIX = (PFNGLXGETFBCONFIGATTRIBSGIXPROC)
@@ -722,8 +731,13 @@ void _glfwPlatformSwapInterval(int interval)
                                          window->X11.handle,
                                          interval);
     }
-    else if (_glfwLibrary.GLX.SGI_swap_control)
-        _glfwLibrary.GLX.SwapIntervalSGI(interval);
+    else if (window->GLX.MESA_swap_control)
+        window->GLX.SwapIntervalMESA(interval);
+    else if (window->GLX.SGI_swap_control)
+    {
+        if (interval > 0)
+            window->GLX.SwapIntervalSGI(interval);
+    }
 }
 
 
diff --git a/src/x11_platform.h b/src/x11_platform.h
index f87287b1..39593655 100644
--- a/src/x11_platform.h
+++ b/src/x11_platform.h
@@ -97,6 +97,10 @@
 #define _GLFW_CONVERSION_SUCCEEDED      1
 #define _GLFW_CONVERSION_FAILED         2
 
+#ifndef GLX_MESA_swap_control
+typedef int (*PFNGLXSWAPINTERVALMESAPROC)(int);
+#endif
+
 
 //========================================================================
 // GLFW platform specific types
@@ -242,6 +246,7 @@ typedef struct _GLFWlibraryGLX
     // GLX extensions
     PFNGLXSWAPINTERVALSGIPROC             SwapIntervalSGI;
     PFNGLXSWAPINTERVALEXTPROC             SwapIntervalEXT;
+    PFNGLXSWAPINTERVALMESAPROC            SwapIntervalMESA;
     PFNGLXGETFBCONFIGATTRIBSGIXPROC       GetFBConfigAttribSGIX;
     PFNGLXCHOOSEFBCONFIGSGIXPROC          ChooseFBConfigSGIX;
     PFNGLXCREATECONTEXTWITHCONFIGSGIXPROC CreateContextWithConfigSGIX;
@@ -250,6 +255,7 @@ typedef struct _GLFWlibraryGLX
     GLboolean   SGIX_fbconfig;
     GLboolean   SGI_swap_control;
     GLboolean   EXT_swap_control;
+    GLboolean   MESA_swap_control;
     GLboolean   ARB_multisample;
     GLboolean   ARB_create_context;
     GLboolean   ARB_create_context_profile;